Electrical contact socket



Mirch 1964 c. c. ANDERSON ETAL 3, 2 29 ICAL CONTACT SOCKE ELECTR T, AND APPARATUS AND METHOD FOR MAKING THE SAME Filed April 27, 1961 3 Sheets-Sheet 1 INYENTORS. M g ,i/w/

March 3, 1964 c. c. ANDERSON ETAL 3,123,429

ELECTRICAL CONTACT SOCKET. APPARATUS AND METHOD FOR MAKING SAME Filed April 27, 1961 3 Sheets-Sheet 2 .7 V W k 1111111111,

(#02455 C. JQA/DEESON ,7 .Ba R/NEfi/HET 3/ l5, INVENTORS.

am d/wu/ MaI'Ch 1964 c. c. ANDERSON ETAL 3,

, ELECTRICAL CONTACT SOCKET, AND APP AND METHOD FOR KING THE SAM Filed April 27, 1961 ARATUS 3 Sheets-Sheet 5 w 5 mm N I E m m 09 ""VIIIEV N 0 I l v W T 0 \Q Q N T 6 /92455 CI flzvo Roy B. R/NEI-m United States Patent 3,123,42h ELECTRICAL CUNIAC'I SUCKET, AND APPA- RATUS AND METHGD FUR MAKING Til-IE SAME Charles C. Anderson, Costa Mesa, and Roy B. Rinehart, Santa Ana, Calif, assignors to Cannon Electric Con parry, L'os Angeles, Calif., a corporation of California Filed Apr. 2.7, 1961, Ser. No. 106,044 11 (Ilaims. (Cl. 339258) This invention relates to the electrical connector art and in particular to an improved electrical contact socket for use with any standard or other suitable contact pin, as well as to one form of apparatus and one method for making the contact socket.

Elongated tubular or sleeve type socket contacts in general are well known, and there are various forms which function properly under congenial circumstances. Some of them depend for inherent spring action to assure a good frictional seating of the mating pin against constrictions in the body of the sleeve or socket, or against the primary surface of the tubular member. In such cases the sleeve must possess the characteristics of a spring material, and some materials which offer suitable spring action are not the best conductors which might be selected. Furthermore, sockets or sleeves of this type are costly to manufacture.

There are other types known wherein the socket consists primarily of a solid tubular member provided with an auxiliary spring member, and in these types the spring member is usually of a rather complex shape specially formed and thereafter installed on the socket using special tooling. In these also, the primary function of the spring is to frictional-1y urge the mating pin into intimate electrical contact with a surface portion of the socket. Those sockets wherein the spring member is specially formed and subsequently installed may be satisfactory from an electrical standpoint, but they are expensive to produce, difficult to automate for production assembly, and they have the further disadvantage that they usually cannot be used on a crimp type socket which is forcibly inserted through a rubber insulator. The reason for the latter deficiency is that the rubber tends to tear the spring clip off the socket when the latter is being inserted.

A broad object of the present invention is to overcome the several disadvantages enumerated.

In more detail, an object of the present invention is to produce a contact socket which externally has the form of a tube without projecting appurtenances and wherein a spring is located entirely internally of the tubular portion which spring provides the function of yieldably urging a mating pin into frictional and electrical contact with an internal wall surface of the tubular member.

A further object of the invention is to provide a contact socket of the type identified wherein the tubular primary electrical conductor portion of the socket contact can be made of the most suitable conductive material, either by drilling a rod or starting with a tubular form, and wherein the spring of a material having the desired characteristics is formed and inserted into the tube in one continuous operation. The latter offers marked advantages in the speed of manufacture, which can be accomplished on a compact automatic machine, with a consequent economy in the cost of manufacture.

The foregoing and other objects and advantages of the invention will become more fully apparent from a consideration of the detailed description which follows taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a greatly magnified longitudinal section through a contact socket embodying the invention, utilizing a first form of spring.

FIGURE 2 is a view similar to FIGURE 1 illustrating a contact pin fully inserted into the socket.

3,123,429 Patented Mar. 3, 1964 'ice FIGURE 3 is a cross-section taken on the line 33 of FIGURE 2.

FIGURE 4 is a cross-section taken on the line 4-4 of FIGURE 1.

FIGURES 5, 6 and 7 are vertical sectional views illustrating in simplified form the elements of an apparatus for forming the spring, inserting it in the socket and performing an indentation operation.

FIGURE 8 is a series of longitudinal cross-sectional views illustrating the sequential forms of the tube and spring assembly resulting from the steps of the method employed commencing with an empty tubular member and terminating with a finished contact socket.

FIGURES 9 and 10 are views generally similar to FIGURES 6 and 7 illustrating a second form of punch used for forming a second form of spring.

FIGURE 11 is a longitudinal sectional of a socket with the second form of spring installed therein.

Referring now to FIGURE 1, the finished contact socket 14 comprises an elongated tubular shell 15 comprisingeither as a solder pot or for crimping, to effect connection with a conductor C shown in phantom. Initial formation of the tubular member '15 can be achieved by different optional methods or means, as for example, either by drilling into a solid rod, or by employing a tubular shell having a cylindrical plane bore 21 (see FIG- URE 8).

The completed socket has a chamfered entrance ramp 13 formed by an internal head for reception of a mating pin 19. The minimum diameter of the ch-amfered ramp 13 is less than the basic circular internal diameter of the tube 16 by a measurement which slightly exceeds the thickness of a spring to be described.

The spring, generally numbered 20, is of a ribbon leaf spring type and includes an elongated flatly bowed main portion 22 extending most of the length of the internal bore 21 of the tube 15, having a return bond 23 adjacent the inner end of the bore 21, and terminating with a relatively short, slightly bowed end section 24. As shown, both bows of the spring project convexly toward the axis of the tube.

The convex depth of the bowed portion 22 is sufficient to intrude into the cylindrical plane of the pin 19, so that when the pin is inserted into the socket this bowed portion of the spring will engage the contiguous surface of the pin and urge the pin diametrically toward the opposite internal surface of the tube 15.

The tube is preferably formed with an elongated indentation 25 in the nature of a crimp, which affords an extended surface 26 for contact with the pin. This surface 26 preferably is arcuate in cross-section, conforming in general to the cross-sectional circumferential contour of the pin, (see FIGURE 3).

A unique and important feature of the spring itself is its arcuate cross-sectional form of the sections 22 and 24 struck as generally illustrated in FIGURES 3 and 4. This form results from the means and method employed in fabricating and pushing the spring into position in the tube, and it offers the advantage of presenting a more than tangential cross-sectional contact surface for engagement with the cylindrical surface of the pin as well as imparting a decided strength to the spring not found in a flat ribbon type spring of the same material and overall dimensions. The forward end 30 of the spring 20 terminates short of an internal annular abutment face 3 1 afforded by the rearward surface of the head which provides chamfered entrance ramp 1'8, so that when the how 22 of the spring 26 is flattened by insertion of the pin 19 there is an escape area for the spring to enter.

This relationship of the forward end of the spring 30 and the annular abutment 31 also serves as a secondary obstacle to prevent withdrawal of the spring when the pin is withdrawn from the socket. The bend 23 and short section 24 of the spring provide the primary anchoring and locating means, the forward end of the section 24 being in relatively close proximity to the rear end of the indentation 25.

While this form of socket may be in practically any size, it has greatly significant value for application in the miniature and sub-rniniature sizes such as size 243* and even smaller, size 20 being in the general magnitude of .040 inch pin diameter.

The general steps performed in fabricating the socket are illustrated in FIGURE 8. Thus in the first view we see a plain open ended tubular member 59 with a contact end -1 and a wire termination end 52. In the second view we observe that the spring has been formed and pushed into position in the bore 21 of the tube. The third view illustrates formation of the identation 25 which has been pressed into the wall of the tube to provide the pin contact section 26. The fourth and final view illustrstes the result of a series of operations whereby the open pin end of the tube is spun or rolled in a head to form the chamfered entrance ramp 1%.

The method step identified may be performed by hand, but for production purposes will be done by automatic machinery which is illustrated in elementary form in FIGURES 5, 6 and 7.

Thus, a roll of ribbon spring material such, for example, as stainless steel ribbon 55, is fed past a cutting station 56 where a reciprocating knife 57 severs the flat rib bon to free a length of steel ribbon 58 which is to form the spring.

This ribbon length 58 reposes in a guide slot on and rests against a stop 61 at a punching station generally designated 62. At this station a punch 63 adapted to advance and retract by any suitable power means and being guided in a punch guide 64 is advanced against the section of steel ribbon '58. The punching station 62 includes a spring forming die as having a cylindrical cavity 67 formed with a countersink 63 for reception of the forward end of tube 53. The tube is held in the axial position shown by any suitable means, as for example, a post 69, and against axial dislodgment by any suitable stop such as '72.

The punch is cylindrical in external form, and the clearance between the external diameter of the punch and the internal cylindrical diameter of the die cavity 67 is sufficiently close that as the punch 53 advances it draws the spring steel ribbon 5'3 over the slightly rounded corner surface 70 of the die entrance and also (except at the return bend 23) squeezes the ribbon from its initial flat condition into an arcuate cross-section. i re center of the punch is substantially offset from the longitudinal center of the spring strip in order to provide the relatively long spring how 22 and the relatively short end section 24. The diameter of the die cavity 67 is slightly less than that of the bore 21 in the tube, and they are axially aligned during formation of the spring.

The stroke of the punch is such that in one continuous forward movement the spring is formed by being drawn through the die 66 and is pushed into the open tube Ell until the bend 23 of the spring lodges against the inner end of the bore 21. The metal of the spring strip is set with a bowed configuration by the drawing action, and although it is momentarily flattened while the punch is in the tube, upon withdrawal of the punch the spring will remain lodged in the tube 5%, and the bow will assume its normal shape as generally illustrated in FEGURES 1 and 8. Thus the forward end 3% of the spring how 22 and a rearward end portion 5% are in engagement with the wall of the tubular bore, and at least the end portions of the short bow 2d are seated against the tubular wall diametrically opposite the how 22.

An indentation or crimping punch is employed to form the indentation 25. This punch may be of standard or conventional type but should be utilized in a manner to assure orientation of the socket tube with respect to the crimping tool jaw so that the indentation 25 is made substantially diametrically opposite the long bow 22 of the spring.

At spinning and forming stations (not shown), the entrance ramp 18 is spun or formed at the mouth of the tube. This may be accomplished by known metal moving means and methods.

The second form of spring 1% and its relationship to the tubular shell are shown in FIGURES 9ll. This form is produced by a punch till reciprocating in a die d6 generally similar to the die 66. The punch 101 is formed with a beveled forward end 162 shaped like a wedge. It imparts to the spring wil relatively sharp angular bends 1 23 and ind with a generally fiat end leg 105. The bend 1% between the long bow 153-6 and the end leg 1% is preferably acute, and the bend llld between the end leg and the short bow 2P7 is preferably obtuse.

The operations of forming this spring and inserting it in the tubular shell, and thereafter effecting modifications in the shape of the shell are the same as described for the first form of spring. The sprin itltl may be used to particular advantage in the relatively larger sizes of contacts, such as 16 to 0.

The special configuration employed allows outside stresses, such as the mating pin contact, to be carried by all three segments of the spring member, namely the long bow res, the end leg 1%, and the short bow MP7. The rear end bearing of the occurs where the bend 1% seats at the junction 168 of the bore 21 with its end wall res, and also where the bend Nd seats against the Wall of the bore diametrically opposite but slightly forward of the junction point While we have herein shown and described our invention in what we have conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of our invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices, apparatus and methods.

What we claim as new and desire to secure by Letters Patent is:

1. An electrical contact socket adapted for mating with a contact pin and comprising a tubular member of conductive material, said tubular member having a bore therein with front and rear ends, the front end of the bore being open, and stop means at the rear end of the bore, the wall of the bore along one side thereof having an elongated raised portion spaced forwardly of said stop m ns so as to provide an elevated surface which the conta pin may engage, the wall of the here on said one side thereof between said raised portion and said stop means being radially outwardly oifset with respect to said raised portion and forming a side pocket, with the wall of the bore between said raised and offset portions presenting a rearwardly facing shoulder, and an elongated, unitary leaf spring member lodged in said bore and comprising a relatively long section and a relatively short section joined toget rer by an end section, said end section being disposed adjacent to said stop means and being engageable therewith to resist rearward axial displacement of the spring member in the bore, saic relatively short section extending forwardly from said end section in said side pocket with the forward end of said relatively short section disposed rearwardly of shoulder in the bore whereby said relatively short section will not obstruct insertion of the contact pin into the bore beyond the raised portion of the bore, and said relatively long section extending forwardly from said end section along the opposite side of the wall of bore from said raised portion, said long section being formed with a bow projecting convexly toward the axis of the bore, whereby a contact pin inserted through the open front end into the bore of the tube will encounter the bow of the leaf spring member and be urged by the latter diametrically of the tubular bore into contact with said raised portion of the wall of the bore.

2. An electrical contact socket as defined in claim 1, wherein said relatively short section of the spring member has a shallow bow therein having its convex side directed toward the axis of the bore.

3. An electrical contact socket as defined in claim 1, wherein both said relatively long section and said relatively short section of the spring are formed with an arcuate cross-section curving in the same general direction as the curvature of the cross-section of the bore.

4. An electrical contact socket as defined in claim 1, wherein said raised portion of the wall of the bore is generally semicircular in cross-section.

5. An electrical contact socket as defined in claim 1, 'wherein said tubular member has an internal bead formed therein proximate its front end, said bead being engageable with the forward end of said relatively long section of the spring member to resist forward axial displacement of the spring member in the bore.

6. An electrical contact socket as defined in claim 1, wherein the junctures between said end section of the spring member and said relatively long and relatively short sections of the spring member comprise rounded corners.

7. An electrical contact socket as defined in claim 1, wherein the junctures between said end section of the spring member and said relatively long and relatively short sections of the spring member comprise relatively sharp corners.

8. An electrical contact socket as defined in claim 7, wherein said end section of the spring member is angled forwardly from the corner between the end section and the relatively long section toward the corner between the end section and the relatively short section.

9. An electrical contact socket adapted for mating with a contact pin and comprising a tubular member of conductive material, said tubular member having a bore therein with front and rear ends, the front end of the bore being open, and stop means at the rear end of the bore, a rearward portion of the wall of the bore along one side thereof adjacent to said stop means being radially outwardly ofiset with respect to the major portion of the wall of the bore on said one side thereof so as to form a side pocket, and an elongated, unitary leaf spring member lodged in said bore and comprising a relatively long section and a relatively short section joined together by an end section, said end section being disposed adjacent to said stop means and being engageable therewith to resist rearward axial displacement of the spring member in the bore, said relatively short section extending forwardly from said end section in said side pocket and being no longer than the axial extent of said side pocket whereby said relatively short section will not obstruct insertion of the contact pin into the bore beyond the forward end of the relatively short section, and said relatively long section extending forwardly from said end section along the Wall of the bore on the opposite side of the bore from said side pocket, said long section being formed with a bow projecting convexly toward the axis of the bore, whereby a contact pin inserted through the open front end into the bore of the tube will encounter the bow of the leaf spring member and be urged by the latter diametrically of the tubular bore into contact with the wall of the bore on said one side thereof forward of said side pocket.

10. An electrical contact socket adapted for mating with a contact pin and comprising a tubular member of conductive material, said tubular member having a bore therein with front and rear ends, the front end of the bore being open, and stop means at the rear end of the bore, a major portion of the wall of the bore along one side thereof comprising an elongated raised surface which the contact pin may engage, said raised surface having an arcuate cross-section of smaller radius than the wall of the bore on the opposite side of the bore from said raised surface, and an elongated, unitary leaf spring member lodged in said bore and comprising a relatively long section and a relatively short section joined together by an end section, said end section being disposed adjacent to said stop means and being engageable therewith to resist rearward axial displacement of the spring member in the bore, said relatively short section extending forwardly from said end section along said one side of the bore, and said relatively long section extending forwardly from said end section along the wall of the bore on said opposite side of the bore, said long section being formed with a bow projecting convexly toward the axis of the bore, whereby a contact pin having a cross-sectional radius of curvature approximately equal to the radius of curvature of said raised surface, when inserted through the open front end into the bore of the tube, will encounter the bow of the leaf spring member and will be urged by the latter diametrically of the tubular bore into an area contact relationship with said raised surface.

11. An electrical contact socket as defined in claim 10 wherein said surface is generally semicylindrical.

References Cited in the file of this patent UNITED'STATES PATENTS 1,677,133 Ford July 17, 1928 1,890,617 Lamy Dec. 13, 1932 2,340,360 Alden Feb. 1, 1944 2,490,317 Ostrak Dec. 6, 1949 2,563,761 Uline Aug. 7, 1951 2,780,792 Eanl Feb. 5, 1957 2,953,765 Greasley Sept. 20, 1960 2,969,517 Gluck Jan. 24, 1961 2,979,689 Jackson et al Apr. 11, 1961 

1. AN ELECTRICAL CONTACT SOCKET ADAPTED FOR MATING WITH A CONTACT PIN AND COMPRISING A TUBULAR MEMBER OF CONDUCTIVE MATERIAL, SAID TUBULAR MEMBER HAVING A BORE THEREIN WITH FRONT AND REAR ENDS, THE FRONT END OF THE BORE BEING OPEN, AND STOP MEANS AT THE REAR END OF THE BORE, THE WALL OF THE BORE ALONG ONE SIDE THEREOF HAVING AN ELONGATED RAISED PORTION SPACED FORWARDLY OF SAID STOP MEANS SO AS TO PROVIDE AN ELEVATED SURFACE WHICH THE CONTACT PIN MAY ENGAGE, THE WALL OF THE BORE ON SAID ONE SIDE THEREOF BETWEEN SAID RAISED PORTION AND SAID STOP MEANS BEING RADIALLY OUTWARDLY OFFSET WITH RESPECT TO SAID RAISED PORTION AND FORMING A SIDE POCKET, WITH THE WALL OF THE BORE BETWEEN SAID RAISED AND OFFSET PORTIONS PRESENTING A REARWARDLY FACING SHOULDER, AND AN ELONGATED, UNITARY LEAF SPRING MEMBER LODGED IN SAID BORE AND COMPRISING A RELATIVELY LONG SECTION AND A RELATIVELY SHORT SECTION JOINED TOGETHER BY AN END SECTION, SAID END SECTION BEING DISPOSED ADJACENT TO SAID STOP MEANS AND BEING ENGAGEABLE THEREWITH TO RESIST REARWARD AXIAL DISPLACEMENT OF THE SPRING MEMBER IN THE BORE, SAID RELATIVELY SHORT SECTION EXTENDING FORWARDLY FROM SAID END SECTION IN SAID SIDE POCKET WITH THE FORWARD END OF SAID RELATIVELY SHORT SECTION DISPOSED REARWARDLY OF SAID SHOULDER IN THE BORE WHEREBY SAID RELATIVELY SHORT SECTION WILL NOT OBSTRUCT INSERTION OF THE CONTACT PIN INTO THE BORE BEYOND THE RAISED PORTION OF THE BORE, AND SAID RELATIVELY LONG SECTION EXTENDING FORWARDLY FROM SAID END SECTION ALONG THE OPPOSITE SIDE OF THE WALL OF THE BORE FROM SAID RAISED PORTION, SAID LONG SECTION BEING FORMED WITH A BOW PROJECTING CONVEXLY TOWARD THE AXIS OF THE BORE, WHEREBY A CONTACT PIN INSERTED THROUGH THE OPEN FRONT END INTO THE BORE OF THE TUBE WILL ENCOUNTER THE BOW OF THE LEAF SPRING MEMBER AND BE URGED BY THE LATTER DIAMETRICALLY OF THE TUBULAR BORE INTO CONTACT WITH SAID RAISED PORTION OF THE WALL OF THE BORE. 